The purpose of this study is to examine immunocytochemically the process of myelin breakdown and regeneration. A number of antibodies will be used including antibodies to myelin basic protein, myelin associated glycoprotein and several new monoclonal antibodies. Experimental demyelination induced chemically by lysolecithin, by JHM virus infection and immunologic demyelination will be compared with human demyelinating disease specimens stained retrospectively. By comparing human and animal demyelination, we hope to obtain new clues to the mechanism of demyelination in multiple sclerosis.